The present invention relates to a vehicle travel aiding device for use in a vehicle, which device is capable of sensing running conditions of the vehicle and generating travel aiding information such as an alarm for a short distance from a preceding vehicle, running guide and so on.
Japanese laid-open patent publication No. 60-91500 discloses such a vehicle travel aiding device that continually senses the distance from another vehicle running ahead of the vehicle with the device and, when a measured distance becomes shorter than a proper intervehicular distance, produces an alarm and gives a command to make an automatic brake operate to keep the proper distance.
Japanese laid-open patent publication No. 62-81591 also discloses such a vehicle travel aiding device that can detect an obstruction ahead of the vehicle and produce an alarm when the distance from the obstruction becomes shorter than a specified value.
Japanese laid-open patent publication No. 4-290200 also discloses such a vehicle travel aiding device that can exchange data of driving conditions such as current position, running speed and running direction of other vehicles ahead of and behind the vehicle and issues an alarm when a danger of collision may arise therebetween.
Japanese laid-open patent publication No. 63-163210 discloses such a vehicle travel aiding device that determines a current location of the vehicle and indicates it along a preset travelling route on a road map indicated on a display screen and outputs a guiding instruction for turning to the right or the left at a crossing on the preset route when the vehicle is just passing a point at a specified distance from said crossing.
The problems involved in the above-mentioned prior arts devices are as follows:
A vehicle travel aiding information such as an alarm when sensing a dangerous approach of another vehicle or a guiding instruction when approaching to a specified crossing is issued at a constant specified timing, neglecting the possible influence of circumstances. Such information, therefore, may not effectively help one to drive the vehicle, for example, in rain or at night.
When a driver drives his vehicle on a super highway or a mountain road, he must be provided with correct and suitable information in consideration of the actual road conditions, which can not be provided by the prior art devices designed for only periodical generation of simple guiding data.
There is still such a problem that every driver may have his own response to an alarm on a short intervehicular distance and, therefore, the alarm issued at a fixed timing determined by a specified calculation may be too early or too late for one to operate the vehicle's accelerator or brake in correct time.